Expositor's Bible Commentary Commentary Matthew 1:18

"Now the birth of Jesus Christ was on this wise: When his mother Mary had been betrothed to Joseph, before they came together she was found with child of the Holy Spirit." — Matthew 1:18 (ASV)

The word translated “birth” (GK 1161; translated “genealogy” in v.1) refers to the beginnings of Jesus Messiah. A pledge to be married was legally binding.

Only a divorce writ could break it, and infidelity at that stage was considered adultery (cf. Dt 22:23–24). Mary herself does not figure largely in Matthew.

“Before they came together” refers here to sexual intercourse, occurring at the formal marriage when the “wife” moved in with her “husband.” Only then was this act proper. The phrase affirms that Mary’s pregnancy was discovered while she was still betrothed, and the context presupposes that both Mary and Joseph had been chaste.

Mary’s pregnancy came about through the Holy Spirit (even more prominent in Luke’s birth narratives). The power of the Lord, manifest in the Holy Spirit who was expected to be active in the Messianic Age, miraculously brought about the conception.